Wet Pre-Concentration of Low-Grade Hematite in High-Pressure Grinding Roller

2012 ◽  
Vol 454 ◽  
pp. 363-368
Author(s):  
Zhi Tao Yuan ◽  
Lei Liu ◽  
Yue Xin Han
Keyword(s):  
High Pressure ◽  
Low Grade ◽  
Lower Grade ◽  
Lower Yield ◽  
Magnetic Separator ◽  
Full Size ◽  
Percentage Points ◽  
Background Magnetic Field ◽  
Concentrate Grade ◽  
Ferromagnetic Medium

The wet pre-concentration of comminuted hematite in high-pressure grinding roller was studied, using the cylindrical ferromagnetic medium in a high gradient magnetic separator. The effects of various factors including rod diameter, rod gap and background magnetic field intensity (BMFI) on the performances of pre-concentration in different size feeds are emphatically investigated. The results showed that as the rod diameter increased, the rod gap decreased and the BMFI increased, the tailings grade and the tailings yield reduced, but the concentrates recovery raised. This variation was regardless of the feed size distribution. After the classifying pre-concentration, the overall concentrate grade increases by 9.56 percentage points and the concentrate recovery is up to the 82.67% with a tailing grade of 10.68% and a tailing yield of 40.31%. Compared with the classifying pre-concentration, the full size pre-concentration produced a concentrate with a lower grade only increased by 6.61 percentage points and the higher recovery of 92.32%. The tailings, with a lower yield of only 26.62% and a lower grade of 7.39%, was mainly produced from the fine feed. The coarse feed in the full size pre-concentration was not separated effectively.

Siderite Beneficiation with Magnetic Separation-Flotation Combined Method

2015 ◽  
Vol 1092-1093 ◽  
pp. 1460-1463 ◽  
Author(s):  
Jin Hua Cheng ◽  
Qin Bo Cao ◽  
Meng Wu
Keyword(s):  
Magnetic Separation ◽  
Mineral Composition ◽  
Simple Structure ◽  
Low Grade ◽  
Lower Grade ◽  
Combined Method ◽  
Composition And Structure ◽  
Grinding Conditions ◽  
Concentrate Grade ◽  
Two Stages

Exploratory experiments were conducted according to the property of a siderite mineral composition and structure has the advantages of simple structure, low grade theory. The siderite Contain Fe 27.46%, Pb 0.97%. First magnetic Fe separation, because of the lower grade ore, for the two stages selection, In 90% of the fineness, good beneficiation indexes, Fe concentrate grade reaches 45.49%, the recovery reached 96.21%. The Fe tailings of magnetic separation in the 90% fineness of flotation tailings Pb test, The tailings in without further grinding conditions, after two stages of cleaning grade is still difficult to improve, Pb concentrate grade of 2.64%, recovery reached 46.96%, Observed in the tests of carbon in tailings interference, because well floatability of carbon, and the dissemination too small it is difficult to remove, so lead to difficulty for improving the grade of the lead concentrate.

scholarly journals Selection of Optimal Magnets for Traction Motors to Prevent Demagnetization

Machines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 124
Author(s):  
Dantam Rao ◽  
Madhan Bagianathan
Keyword(s):  
Flux Density ◽  
Electric Vehicles ◽  
Parallel Line ◽  
Low Grade ◽  
Lower Grade ◽  
Worst Case ◽  
Traction Motors ◽  
Knee Point ◽  
Point Of Intersection ◽  
Selection Of

Currently, permanent-magnet-type traction motors drive most electric vehicles. However, the potential demagnetization of magnets in these motors limits the performance of an electric vehicle. It is well known that during severe duty, the magnets are demagnetized if they operate beyond a ‘knee point’ in the B(H) curve. We show herein that the classic knee point definition can degrade a magnet by up to 4 grades. To prevent consequent excessive loss in performance, this paper defines the knee point k as the point of intersection of the B(H) curve and a parallel line that limits the reduction in its residual flux density to 1%. We show that operating above such a knee point will not be demagnetizing the magnets. It will also prevent a magnet from degenerating to a lower grade. The flux density at such a knee point, termed demag flux density, characterizes the onset of demagnetization. It rightly reflects the value of a magnet, so can be used as a basis to price the magnets. Including such knee points in the purchase specifications also helps avoid the penalty of getting the performance of a low-grade magnet out of a high-grade magnet. It also facilitates an accurate demagnetization analysis of traction motors in the worst-case conditions.

Missed Shots at the Free-Throw Line

2015 ◽  
Vol 18 (6) ◽  
pp. 539-559 ◽  
Author(s):  
Mattie Toma
Keyword(s):  
High Pressure ◽  
National Collegiate Athletic Association ◽  
Statistical Significance ◽  
National Basketball Association ◽  
Choking Under Pressure ◽  
Professional Basketball ◽  
Free Throw ◽  
Percentage Points ◽  
Male College ◽  
The Impact

Choking under pressure represents a phenomenon in which individuals faced with a high-pressure situation do not perform as well as would be expected were they performing under normal conditions. In this article, I identify determinants that predict a basketball player’s susceptibility to choking under pressure. Identification of these determinants adds to our understanding of players’ psychology at pivotal points in the game. My analysis draws on play-by-play data from ESPN.com that feature over 2 million free-throw attempts in women’s and men’s college and professional basketball games from the 2002-2013 seasons. Using regression analysis, I explore the impact of both gender and level of professionalism on performance in high-pressure situations. I find that in the final 30 seconds of a tight game, Women’s National Basketball Association and National Basketball Association players are 5.81 and 3.11 percentage points, respectively, less likely to make a free throw, while female and male college players are 2.25 and 2.09 percentage points, respectively, less likely to make a free throw, though statistical significance cannot be established among National Collegiate Athletic Association women. The discrepancy in choking between college and professional players is pronounced when comparing male college players who do and do not make it to the professional level; the free-throw performance of those destined to go pro falls 6 percentage points more in high-pressure situations. Finally, I find that women and men do not differ significantly in their propensity to choke.

CASE STUDY ON CIRCUMSCRIBED GLIOMAS, THEIR CLINICOPATHOLOGICAL CORRELATION IN A TERTIARY CARE CENTER

2021 ◽  
pp. 42-45
Author(s):  
Esther Alffi Papang ◽  
K. Rama
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Tertiary Care ◽  
Biological Behavior ◽  
Low Grade ◽  
Lower Grade ◽  
Who Grade ◽  
Primary Tumors ◽  
Short Period ◽  
The Impact

The histogenesis and biological behavior of primary tumors of the central nervous system(CNS) are very diverse. The majority of present gliomas as benign, slow growing lesions classied as by the WHO classicati grade I or II (Low grade gliomas) on of CNS tumors. However, a signicant fraction of gliomas develop over a short period of time and progress rapidly and are therefore classied as WHO grade III or IV(High grade gliomas). Astrocytomas are primary central nervous system tumours that can develop in adults or in children. They arise from the Astrocytes. They can be divided into diffuse that generally have a higher grade and poorer prognosis and those that are localised that tend to be of a lower grade and have a better prognosis. In this study, we outline the basic histological spectrum and features, epidemiological aspects and grade of circumscribed gliomas (localised) or other Astrocytic tumours according to WHO classication . These are the Pilocytic Astrocytoma, Pilomyxoid Astrocytoma, Subependymal giant cell Astrocytoma, Pleomorphic xanthoastrocytoma and Anaplastic astrocytoma . The knowledge of these tumours are important as they are one of the commonest cause of mortality and morbidity in both the young and old, accounting for about 60% of the glial tumours. Therefore neuropathological diagnosis and tumour characteristics will therefore profoundly inuence the impact of treatment strategies.

scholarly journals Development and Validation of an Efficient MRI Radiomics Signature for Improving the Predictive Performance of 1p/19q Co-Deletion in Lower-Grade Gliomas

Cancers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 5398
Author(s):  
Quang-Hien Kha ◽  
Viet-Huan Le ◽  
Truong Nguyen Khanh Hung ◽  
Nguyen Quoc Khanh Le
Keyword(s):  
Gold Standard ◽  
Binary Classification ◽  
Predictive Performance ◽  
Deletion Mutation ◽  
Gradient Boosting ◽  
Low Grade ◽  
Lower Grade ◽  
Chromosome 1P ◽  
Extreme Gradient Boosting ◽  
External Test

The prognosis and treatment plans for patients diagnosed with low-grade gliomas (LGGs) may significantly be improved if there is evidence of chromosome 1p/19q co-deletion mutation. Many studies proved that the codeletion status of 1p/19q enhances the sensitivity of the tumor to different types of therapeutics. However, the current clinical gold standard of detecting this chromosomal mutation remains invasive and poses implicit risks to patients. Radiomics features derived from medical images have been used as a new approach for non-invasive diagnosis and clinical decisions. This study proposed an eXtreme Gradient Boosting (XGBoost)-based model to predict the 1p/19q codeletion status in a binary classification task. We trained our model on the public database extracted from The Cancer Imaging Archive (TCIA), including 159 LGG patients with 1p/19q co-deletion mutation status. The XGBoost was the baseline algorithm, and we combined the SHapley Additive exPlanations (SHAP) analysis to select the seven most optimal radiomics features to build the final predictive model. Our final model achieved an accuracy of 87% and 82.8% on the training set and external test set, respectively. With seven wavelet radiomics features, our XGBoost-based model can identify the 1p/19q codeletion status in LGG-diagnosed patients for better management and address the drawbacks of invasive gold-standard tests in clinical practice.

CBIO-05. SOX2 CHROMATIN ARCHITECTURE AND ENHANCER ACTIVITY IN THE MAINTENANCE AND DEVELOPMENT OF NEURAL STEM CELLS

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi28-vi28
Author(s):  
Devin Bready ◽  
Aram Modrek ◽  
Joshua Frenster ◽  
Jane Skok ◽  
Dimitris Placantonakis
Keyword(s):  
Stem Cells ◽  
Neural Stem Cells ◽  
Developmental Process ◽  
Embryonic Stem ◽  
Stem Cell Differentiation ◽  
Ctcf Binding ◽  
Low Grade ◽  
Lower Grade ◽  
Cell Of Origin ◽  
Putative Enhancer

Abstract Gain of function mutations in isocitrate dehydrogenase I (IDH1) result in the formation of the oncometabolite 2-hydroxyglutarate (2HG) in adult lower grade gliomas. To gain insight into mechanisms of gliomagenesis, our lab previously created a tractable human cellular model of low grade astrocytoma (LGA) using the putative cell-of-origin, human neural stem cells (NSCs), engineered to express mutant IDH1 and knockdown constructs against TP53 and ATRX, the two other genetic changes that accompany the IDH mutation in these tumors. We found that transcription factor (sex determining region Y)-box 2 SOX2, which is essential to NSC multipotency, the ability to differentiate to neuroglial lineages, behaves as a tumor suppressor during glioma initiation. In this context, we showed SOX2 is transcriptionally downregulated to impair NSC multipotency, thus locking NSCs in an undifferentiated state to initiate gliomagenesis. This downregulation occurs secondary to dynamic reorganization of the topologically associating domain (TAD) of SOX2 and the loss of contact with several genomic loci with histone modifications and chromatin accessibility suggestive of being enhancers. Here we show that those putative enhancers acquire enhancer-like features simultaneous to tje TAD organizing in a way that facilitates interaction with the SOX2 promoter during the process of pluripotent stem cell differentiation into neuroectodermal lineages, suggesting a developmental role. Preliminary data suggests that disruption of the SOX2 TAD by preventing binding of the genome organizer CTCF downregulates SOX2 expression in NSCs. Targeted silencing of several regions of a putative enhancer with CRISPRi also downregulates SOX2. In human embryonic stem cells (hESCs), interfering with these CTCF binding sites biases their differentiation away from the neuroectoderm. We are currently performing CRISPRi screen against all putative enhancer loci, teratoma formation assays on hESCs lacking relevant CTCF binding, and CRISPR mediated deletion of putative enhancers. Understanding this developmental process may reveal underlying vulnerabilities in LGA.

scholarly journals Ivosidenib in Isocitrate Dehydrogenase 1–Mutated Advanced Glioma

2020 ◽  
Vol 38 (29) ◽  
pp. 3398-3406 ◽  
Author(s):  
Ingo K. Mellinghoff ◽  
Benjamin M. Ellingson ◽  
Mehdi Touat ◽  
Elizabeth Maher ◽  
Macarena I. De La Fuente ◽  
...  
Keyword(s):  
Solid Tumors ◽  
Isocitrate Dehydrogenase ◽  
Objective Response ◽  
Progression Free Survival ◽  
Maximum Tolerated Dose ◽  
Adverse Event Rate ◽  
Low Grade ◽  
Lower Grade ◽  
Open Label ◽  
Isocitrate Dehydrogenase 1

PURPOSE Diffuse gliomas are malignant brain tumors that include lower-grade gliomas (LGGs) and glioblastomas. Transformation of low-grade glioma into a higher tumor grade is typically associated with contrast enhancement on magnetic resonance imaging. Mutations in the isocitrate dehydrogenase 1 ( IDH1) gene occur in most LGGs (> 70%). Ivosidenib is an inhibitor of mutant IDH1 (mIDH1) under evaluation in patients with solid tumors. METHODS We conducted a multicenter, open-label, phase I, dose escalation and expansion study of ivosidenib in patients with m IDH1 solid tumors. Ivosidenib was administered orally daily in 28-day cycles. RESULTS In 66 patients with advanced gliomas, ivosidenib was well tolerated, with no dose-limiting toxicities reported. The maximum tolerated dose was not reached; 500 mg once per day was selected for the expansion cohort. The grade ≥ 3 adverse event rate was 19.7%; 3% (n = 2) were considered treatment related. In patients with nonenhancing glioma (n = 35), the objective response rate was 2.9%, with 1 partial response. Thirty of 35 patients (85.7%) with nonenhancing glioma achieved stable disease compared with 14 of 31 (45.2%) with enhancing glioma. Median progression-free survival was 13.6 months (95% CI, 9.2 to 33.2 months) and 1.4 months (95% CI, 1.0 to 1.9 months) for the nonenhancing and enhancing glioma cohorts, respectively. In an exploratory analysis, ivosidenib reduced the volume and growth rates of nonenhancing tumors. CONCLUSION In patients with m IDH1 advanced glioma, ivosidenib 500 mg once per day was associated with a favorable safety profile, prolonged disease control, and reduced growth of nonenhancing tumors.

Management for Different Glioma Subtypes: Are All Low-Grade Gliomas Created Equal?

2019 ◽  
pp. 133-145 ◽  
Author(s):  
Martin C. Tom ◽  
Daniel P. Cahill ◽  
Jan C. Buckner ◽  
Jörg Dietrich ◽  
Michael W. Parsons ◽  
...  
Keyword(s):  
Molecular Genetic ◽  
World Health ◽  
Low Grade ◽  
Lower Grade ◽  
Future Directions ◽  
Molecular Alterations ◽  
Lower Grade Glioma ◽  
Grade 3 ◽  
Health Organization

Following the identification of key molecular alterations that provided superior prognostication and led to the updated 2016 World Health Organization (WHO) Central Nervous System (CNS) Tumor Classification, the understanding of glioma behavior has rapidly evolved. Mutations in isocitrate dehydrogenase (IDH) 1 and 2 are present in the majority of adult grade 2 and 3 gliomas, and when used in conjunction with 1p/19q codeletion for classification, the prognostic distinction between grade 2 versus grade 3 is diminished. As such, the previously often used term of “low-grade glioma,” which referred to grade 2 gliomas, has now been replaced by the phrase “lower-grade glioma” to encompass both grade 2 and 3 tumors. Additional molecular characterization is ongoing to even further classify this heterogeneous group of tumors. With such a colossal shift in the understanding of lower-grade gliomas, management of disease is being redefined in the setting of emerging molecular-genetic biomarkers. In this article, we review recent progress and future directions regarding the surgical, radiotherapeutic, chemotherapeutic, and long-term management of adult lower-grade gliomas.

Direct Reduction Experiment on Low-Grade Limonite at JiangXi

2013 ◽  
Vol 734-737 ◽  
pp. 1029-1032 ◽  
Author(s):  
Jiang An Chen ◽  
Jun Liu
Keyword(s):  
Magnetic Separation ◽  
Direct Reduction ◽  
Influence Factors ◽  
Low Grade ◽  
Iron Concentrate ◽  
Reduction Experiment ◽  
Mesh Screen ◽  
Concentrate Grade ◽  
Roasting Time ◽  
Separation Conditions

Considered the properties of limonite ore at Jiangxi, the raw ore pressing ball - direct reduction - magnetic separation flowsheet have been adopted. the pressing ball conditions, the influence factors and the grinding magnetic separation conditions experiments were carried out. The results shown that: When the dosage of coal was 20%, water was 10%, CMC was 0.5%, pressing ball under the pressure of 190 kN, the calcination temperature was 1100 °C, the roasting time is 50 min, roasted ore were magnetic separated after grinded to 85% through 200 mesh screen. the iron concentrate grade of 92.48% and recovery rate of 93.45% were achieved finally.

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